Recent flat-panel displays such as liquid crystal display devices, for example, have features such as being thinner and lighter than conventional cathode-ray tube displays. This is the reason flat-panel displays are widely used in liquid crystal televisions, monitors, mobile phones, and the like. A liquid crystal panel in such a liquid crystal display device uses an active matrix substrate whereupon a plurality of data wiring lines (also called source electrode wiring lines or signal lines) and a plurality of scanning wiring lines (gate electrode wiring lines or gate lines) are arranged in a matrix. Pixels that each have a switching element such as a thin-film transistor (abbreviated as a “TFT”), which is provided in the vicinity of each intersection between the data wiring lines and scanning wiring lines, and a pixel electrode connected to this switching element, are arranged in a matrix on the active matrix substrate.
To reduce power consumption for a display device provided with the switching element in each pixel in this way, it is effective to lower the driving frequency. However, if the driving frequency is lowered in the liquid crystal panel, the voltage holding period of the liquid crystal pixel becomes longer, resulting in failure to hold the voltage to be applied to the liquid crystal pixel during the holding period, and thus causing display anomalies. Therefore, it is difficult to lower the driving frequency without a drop in display quality.
A configuration of a TFT has been proposed that suppresses the change in voltage of the liquid crystal pixels. This configuration has one end of a liquid crystal pixel connected to a signal line via each drain/source of two TFTs connected in series, and each gate of these two TFTs is connected to a gate line (see Patent Document 1, for example). In this conventional technology, one end of an auxiliary capacitance is connected to the connecting point between these two TFTs, and the other end of the auxiliary capacitance, and the other end of the liquid crystal pixel are respectively grounded. This configuration allowed for a suppression of the change in liquid crystal pixel voltage caused by leakage current when the TFT is non-conductive.